Protective seal for vulcanizing apparatus



Dec. 19, 1950 A. N. GRAY 2,534,865

PROTECTIVE SEAL FOR VULCANIZING APPARATUS Filed June 2Q, 1947 MERCURYINVENTOR A. N. GRAY A T TORNE V Patented Dec. 19, 1950 UNITED STATESrArENT oFFxcE PROTECTIVE SEAL FOR VULCANIZING APPARATUS Alvin N. Gray,Joppa, Md., assignor to Western Electric Company, Incorporated, NewYork, N. Y, a corporation of New York Application June 20, 1947, serialNo. 755,987 a 11 Claims. o1.1s e) covering of vulcanizable compoundincluding sul phur as an agent therein, and then the covered core isadvanced through an elongated vulcanizing tube to vulcanize-thecovering. In a vulcanizing tube having steam at a high temperature andunder high pressure therein, the heat of the steam vaporizes latentmoisture in the hygroscpic elements of the core; The steam in thevulcanizing tube picks up hydrogen sulphide derived from the sulphurused as a vulcanizing agent in the vulcanizable compound extruded uponthe core.

A seal has sometimes been positioned at the endof such a vaulcanizingtube, and cold water has been introduced into the seal. The seal servesthe dual purpose or preventing the escapeof steam from the vulcanizingtube into the atmosphere, and of cooling the covered core to condensethe vaporized moisture originally contained in the hygroscopic elementsof the core and thereby prevent bursting of the covering of vulcanizedcompound thereover. The pressure of the water has sometimes beencontrolled by apparatus such as that disclosed and claimed in copendingapplication Serial No. 702,601, filed October 11, 1945 by A. Stieglerfor Continuous Extruding and Vulcanizing Apparatus. Such a pressurecontrolling apparatus includes a U- tube including a float chambercontaining mercury and a float resting on the mercury in the floatchamber for actuating suitable waterpressure-changing elements. Steampressure is transmitted directly by steam to the float chamber, andwater pressure is transmitted to the other end of the U-tube. In thepast, the steam or condensate carrying hydrogen sulphide therewith hascome into direct contact with the mercury in the float chamber andmercuric sulphide,

and due to the reaction between the hydrogen sulphideand the mercury asolid is formed, which cakes up the float and the mercury chamber. Thishas a deleterious-action on the operation of the-pressurecontrolling-apparatus.

An object of the invention is to provide new and improved protectiveseals.

A further object of theinvention is to providenew and improvedprotective seals for preventing contact between hydrogen sulphide insteam lines connecting vulcanizing tubes of continuous extruding andvulcanizing apparatus and mercury in float chambers of pressureregulating systems associated with such apparatus.

A protective seal illustrative of certain features of the inventionincludes a precipitating chamber positioned between a float chamber containing mercury'and a steam line having hydro- 'gen sulphide laden steamtherein, and a precipitating agent positioned inthe precipitatingchamber for precipitating the sulphide to pre vent'contact between thesulphide and the mercury.

A complete understanding of the invention' maybe'obtained from thefollowing detailed description of a protective seal forming a specificembodiment thereof, when read in conjunction with the appended drawing,in which the only figure is an enlarged, fragmentary, partiallysectional, side elevation of a portion of a continuous insulating andvulcanizing apparatus and a protective seal embodying the invention.

Referring now in detail to the drawing, there is shown therein a portionof a continuous extruding and vulcanizing apparatus for forming andvulcanizing a protective covering Ill (Fig. 1)

over a core I I to form a covered conductor. The core it also includes atextile covering (not shown), such as cotton, or the like, which ishygroscopic in the manner described in the above-mentioned copendingapplication. The covering H7 is composed of a vulcanizable compound,such as a jacketing compound containing rubber or a syntheticrubber-like material and sulphur as a vulcanizing agent.' The coveredcore is advanced through an elongated steam-jacketed vulcanizing tube 22into which steam under high pressure is supplied by suitable means (notshown).

T der a high but fluctuating pressure heats the covering Hi to a hightemperature. I I .and pressure vulcanizezthe. covering 10, but the.

This heat The steam vulcanizes the vulcanizable compound, and, in sodoing, be-

heat of the covering l heats any moisture contained in the textilecovering to temperatures at which the moisture would be volatilizedunder atmospheric pressure. As long as a pressure substantially abovethat of atmosphere is kept 5 on the covering H], the moisture thereunderdoes not volatilize.- wBut-if the pressure thereon is reduced to that.of atmosphere before themoisture is cooled, the moisture under thecovering l9 volatilizes and ruptures or blisters the cover- 10 ing l0.Cold water under a high pressure is supplied through a pipe 28 totheseal andcools, 55;: the moisture in the covered core H sufficiently'to prevent such damage.

The cold water is kept at a pressure:substan--; l5 tially the same asthat of the steam by a differ- 2 Y ential pressure controlling device.29, which, ex-.. cept for a protective seal 30, is identical with thatdisclosed and claimed in the above-mentioned; copending application ofA1 Stiegler. The differehtial: pressure. controlling device: includes aU-tube 3i and a float chambere32; ,-Mercury.po-; sitioned in the U-tube3| serves to support-a fioatc33. in the .float chamberg32, and' thefloat serves-toactuate the-'controller.- -A pipe 41 filled with-.oilconnects-the upper portion-of the float. chamber, the-- upper. portionof which: also is filled with oil, to a manually operable valve 43leading to the interior of. a precipitating tank45.Theprecipitating.tank-isfilled with a-hydrogen sulphide: precipitatingsolution :such :as, for example 'a solutionrotl copperchloride, ofgreater density; thamwateu. and oil, andxhas acollecting portion 46,a;drainq41 and a refill spout 48. The, precipitatingsolutionds heavierthan the-oil in the pipe 42 and ispositioned ata-lowerlevel than,the-floatcchamber32 so that-the; oil prevents contact between themercury and the precipitae-v ting solution but :transmits pressuretherebetween.

A pipes, having a: spout 50 and filledgwith 4e water.-connectstheiprecipitatingitank to-a check. valveeil, rwhichd's connectedto asteam condenser 52'; iThejcheck-valve 5| does not normally: affectthe rest of the apparatus, ,butwhen; a highs vacuum is: formed: ina.1.pipe-54 connecting'the condenser .-to theivulcanizing'tube-22, aswhen steam is initiallyzsupplied to :the vulcanizing tubeandashootsxpast'rthe pipe 54 at a high, velocity, the checkwalve letsatmospheric air into the pipe 49 andsthepondenserntopreventthecontentsof the protective seal; 311 from ,beingdrawngtherefromzm:

In the operation .of the protective-seal 13,0, the--.. pressure of thesteam in the vulcanizing tube 22 is transmitted to, the float chamber 32by steam 55 through thezpiper 54, by water .in the.condenser-,- 52 andthe pipe 49, by the precipitating solutionin the (precipitating tank 45and by oil in the valvef43 and the pipe"4 2.

The; water in the-condenseriZ and the pipe 49 isthe condensate-fromsteam entering --thecondenser, and hence is'ladenwith the-hydro-- gensulphide ?carriedby the. steam: Any hydrogensulphide-which enters thespout;5il of they piped-9 is immediately; precipitated "by reaction withthe m'etallicj-saltin the precipitatingsolution .in:.the-,sp'out; .and.the I precipitate; copper sul-. phide,.-:if a :copper chloride solution1 is; used; settles into the collectingiportiony leof the precipi- Q itating tank. The oil between: the "precipitating:.:: solutionandtheamercury prevents contact there betweenfby. gravity?Thus,-'hydrogenzsulphide is kept;fronr;contacting--the1.merc.ury .sothat the mercury is i kept rcleanr,

Whenever "the .precipitating:solutiombecomes}:v {[5 weak, the valve 43 mclosed and the drain 4'! is opened whereby the solution flushes thecollected precipitate out of the collecting portion 46 of the tank as itis drained from the tank. The drain 4"! then is reclosed, the refillspout 48 is opened, and a fresh quantity of the precipitatingsolutionzis pouredinto the 'tank 45 through the refill. spouteto: fillthe tank-.45. Thereflll spout is closed again and the valve 43 isreopened. The above-described apparatus serves to keep mercury in thefloat chamber 32 from being contaminated'by hydrogen sulphide, so thepressure controller is kept in operative condition even thoughthesteamsin the vulcanizing tube 22 is laden-withhydrogemsulphide. Also,there is no solid LObStLllCtlOl'l between the vulcanizing tube and..thefioatchamber so that transmission of pressure from the steam in the tubeto the mercury-.is:n'ot: prevented.

The precipitating tank :is made sufficiently largesto prevent-thenecessity-of, draining and refilling it frequently. Jheprecipitatingsolution efiectively prevents contactnbetween the hydrogensulphide and. the.oil, .sinc e the spout 50. ex-- tends so far into the.tankvthathydrogensulphide. doesnot filter. through :the-oil and-come.into C0119,

tactwith rthemercuryh What, isclaimed is:

1. In an .apparatus includinga- U-tube for holding mercury and .aconduit for .fluidJaden with a chemicalelementcapable of forming asalt.

with mercury,.the:improyement which comprises.

a chamber communicating with both the conduit and the .U etube;asolution positionedin-the cham-. ber for removing the-chemicalelementinsuch: a fluidin theconduit and. for transmitting pressure fromtheefluid toward-mercury held in them U-tube; and a;pressure-transmitting fluidim-; miscible with ,the-solutioniandl themercury: posi-;

tioned therebetween.

insoluble sulphide and for transmitting pressure from the fluidtowardmercury held in the U-tube,

and,,. a, pressureetransmitting fluid immiscible with the solution andthe mercurypositioned between thesolution andthe mercury.

3. In an apparatus including a-mercury filled. U-tube anda conduitforfluid .laden with hydro-'1 gen sulphide the improvement-which comprises-I a chamberwpositionedgbetween and-communi' eating with both the conduitand one end'ofthe U-tube,-a copper chloride solution. positioned'in thechamberior reacting with thehydrogen sulphide in; the fluidin theconduit to form an insoluble sulphide. and. for transmitting pressurefrom .thefluid toward the mercury in the 'U-tube, ands-a.pressure-transmitting 3 fluid immiscible with the solutionandthe-mercury positioned. be---, .1

tween the solutionand, the mercury.

the second fluid to prevent contact between it and the first-mentionedfluid'and for transmitting pressure from the second fluid toward thefirst-mentioned; fluid, and a pressure-transmitting sealing fluidpositioned between the precipitating fluid and one of the other fluidsand immiscible therewith.

5. In an-apparatusincluding a chamber for holding mercury and a secondchamber for holding a fluid having hydrogen sulphide therein, theimprovement which comprises means including a third chamber forconnecting the firstmentioned chambers and being in communicationtherewith, a sulphide-precipitating fluid contained in the third chamberfor reacting with the hydrogen sulphide of the second fluid to form aninsoluble sulphide toprevent contact between it and mercury in the firstchamber and for transmitting pressure from the second fluid to themercury, and a pressure-transmitting sealing fluid immiscible withmercury and the sulphide-precipitating fluid and positionedtherebetween.

6. In an apparatus including two containers filled with fluids includingchemically reactive elements, a device for connecting the two containerstogether in communication with each other and for preventing contactbetween the two fluids, which comprises a chamber positioned between thetwo containers and connected thereto, a precipitating fluid forprecipitating the reactive elements of one of the fluids in thecontainers to prevent contact between the reactive elements of thelast-mentioned fluids, a pressure-transmitting, sealing fluid immisciblewith the precipitating fluid and one of the other fluids positionedtherebetween, means for draining the chamber to remove the precipitatetherefrom, and means for refilling the chamber.

7. In an apparatus including a container, a container having mercurytherein and a second container having therein a fluid laden with anelement capable of forming a salt with the mercury when in contacttherewith, a device for connecting the two containers in communicationwith each other and for preventing contact between the mercury and thefluid, which comprises a chamber positioned between the two containersand connected thereto, a precipitating fluid for precipitating thesalt-formin|g element of the fluid in the second container to preventcontact between that element and the mercury, a pressure-transmitting,sealing fluid immiscible with the mercury and the precipitating fluidpositioned between and in communication with the mercury and theprecipitating fluid, means for draining the chamber to remove theprecipitate therefrom, and means for refilling the chamber.

8. In an apparatus including a container having mercury therein and asecond container having therein a fluid including hydrogen sulphide adevice for connecting the two containers together in communication witheach other and for preventing contact between the mercury and thehydrogen sulphide, which comprises a chamber positioned between the twocontainers and 9. In a continuous vulcanization apparatus in eluding anelongated vulcanizing tube, a cooling and sealing unit positioned at theexit of the vu1-" mined ratio between the pressures of the steam and thewater, said controlling means including a mercury U-tube for retainingmercury therein, the improvement which comprises a device for protectingthe mercury from contact with the steam and for transmitting pressuretherebetween, which comprises a generally U-shaped precipitatingpassage, a hydrogen sulphide precipitating fluid in the precipitatingpassage, a conduit for connecting one arm of the precipitating passageto one arm of mercury U-tube, a sealing fluid non-reactive with andimmiscible with the mercury and the precipitating fluid positioned inthe conduit, said sealing fluid having a density lower than that of theprecipitating solution, and a second conduit for connecting the otherarm of the precipitating passage to one of the cooling and sealing unit,the water-supplying means and the vulcanizing tube.

10. In a continuous vulcanization apparatus includin an elongatedvulcanizing tube, a cooling and sealing unit positioned at the exit ofthe vulcanizing tube, means for supplying steam under a high pressure tothe vulcanizing tube, means for supplying water under high pressure tothe cooling and sealing unit and means for controlling one of thesteam-supplying means and water-supplying means to maintain apredetermined ratio between the pressures of the steam and the water,said controlling means including a mercury U-tube for retaining mercurytherein, the improvement which comprises a device for protecting themercury from contact wit one of the steam and the water and fortransmitting pressure therebetween, which comprises a generally U-shapedprecipitating passage, a hydrogen sulphide-precipitating fluid includingcopper chloride and having a predetermined density in the precipitatingpassage, a conduit for connecting one arm of the precipitating passageto one arm of the mercury U-tube, oil having a density less than that ofthe precipitating fluid and positioned in the conduit, and a secondconduit for connecting the other arm of the precipitating passage to oneof the cooling and sealing unit and the vulcanizing tube.

ll. In a continuous vulcanization apparatus including an elongatedvulcanizing tube, a coolconnected to the second container, a copper ingand sealing unit positioned at the exit of the vulcanizing tube, meansfor supplying steam under a high pressure to the vulcanizin tube,

means for supplying water under high pressure to the cooling and sealingunit and means for" controlling one of the steam-supplying means and thewater-supplying means to maintain a predetermined ratio between thepressures of the steam and the water, said controlling means including amercury U-tube for retaining mercury therein, the improvement whichcomprises a device for protecting the mercury from contact with one ofthe steam and the water and for transmitting pressure therebetween,which comprises a vertically disposed U-shaped precipitating trap, asulphur and hydrogen sulphide precipitatin fluid of a predetermineddensity positioned in the precipitating p 81 conduitlincludinsramanually: operabl valve for connecting: Qnearm of the precipitating trapto one armofthemercury u-tube, a sealingfluid non-reactivewith andimmiscible with the mercury and the precipitating fluid positionedintheconduit, and having a density less than that-ofthe precipitatingfluid, a second conduit for connecting the other arm of theprecipitating trap to one of the cooling and sealing unit, thewater-supplying means and thevulcanizing tube, means for draining theprecipitating trap, and means for refilling the precipitating U-tube.

' I ALVIN N. GRAY.

8 REFERENCES ,CITED The following references are of recordinthe file ofthis patent:

UNITED V STATES "PATENTS Number Name Date 2,105,127 Petroe Jan, 11;19382,307,575 --Davis Jan. 5,;1943 2,418,166 Dinmore, Jr.,-et al. Apr. 1.-1947 10 2,426,341 Canfield Aug. 26,- 1947

